In an environment in which Machine-to-Machine (M2M) devices are connected to an M2M service provider (SP) through an access network provided by another entity, the M2M service provider effectively creates a service layer on top of the access layer provided by the access network and uses this service layer to deliver services to the M2M devices. However, for the service provider to identify devices on the network, there is a requirement that the service provider network and the access network agree on at least one identifier to be used to reach the M2M device. In the M2M framework developed by the European Telecommunications Standards Institute (ETSI), the M2M Service Provider (SP) interworks with the access network with respect to an M2M device that is subscribed with the M2M SP. This interworking is typically performed using an external identifier specifically selected for that purpose, although other available identifiers that might be used to identify the M2M device include the device's Mobile Station Integrated Services Digital Network-Number (MSISDN) or IP Multimedia Public Identity (IMPU). The external identifier is typically allocated to an M2M service provider by the access network for the M2M device. The external identifier is used for interworking purposes instead of the IMSI, which is typically reserved for use as a private identity by the access network and not used on external (public) interfaces.
Large-scale deployments of M2M devices are anticipated, some of which may require implementation of multiple applications in each of many M2M devices. In some cases, different applications on an M2M device will correspond to different M2M SPs. While in many cases the M2M device will initiate communications through the access network to the external M2M SP(s), in some cases the connectivity provided to the device by the access network should be triggered by the M2M SP. This is the rationale behind a device triggering procedure specified by the 3rd-Generation Partnership Project (3GPP), for use by M2M SPs seeking to initiate a connection with a M2M device from outside a 3GPP access network serving the M2M Device. This device triggering procedure is referred to as MTC Device Triggering by 3GPP, where “MTC” refers to “Machine-Type Communications” and may be regarded as a synonym for “Machine-to-Machine Communications.”
Accordingly, an external identifier is defined in Release 11 of the 3GPP standards, for use by M2M SPs in association with MTC Device Triggering procedures. However, the 3GPP specifications do not describe how external networks can acquire the external identifier for a particular M2M device, for interworking purposes. Furthermore, ETSI M2M standards do not yet consider the use of the MTC Device Triggering procedure, and do not specify a mechanism for acquiring external identifiers for M2M devices from cellular networks or other access networks.